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Light sources

Why can we see light sources ?

Obviously, seeing objects is possible thanks to our eyes.
The human eye is a light receiver that converts this one in nervous signals sent to brain through of the optic nerve.The brain interprets these signals and reconstructs an image.

The term "light receiver" indicates that eye must receive the light emitted by an object so that it can be seen.

Reception of light is possible under some conditions:
- The eye must be oriented so that the light emitted by the object can penetrate its pupil.
- The object must emit enough light so that it can be detected by the eye.
- The area, between eye and observed object, must let pass light. This kind of medium is said " transparent " (as opposed to opaque which qualify a medium that doesn't allow propagation of light)

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